BUTTERNUT
Like the hickory tree, the butternut shares in the childhood
reminiscences of those who have lived on farms or in the country where
butternuts are a treat to look forward to each fall. The nuts, which
mature early, have a rich, tender kernel of mild flavor. Only the
disadvantage of their heavy, corrugated shells prevents them from
holding the highest place in popularity, although a good variety cracks
easily into whole half-kernels.
Butternuts grow over an extended range which makes them the most
northern of all our native wild nut trees, although their nuts do not
mature as far north as hazelnuts do. Butternut trees blossom so early
that in northern latitudes the blossoms are frequently killed in late
spring frosts. Only when the trees are growing near the summit of a
steep hillside will they be likely to escape such frosts and bear crops
regularly. I have found that really heavy crops appear in cycles in
natural groves of butternut trees. My observation of them over a period
of thirty-two years in their natural habitat in west-central Wisconsin
has led me to conclude that one may expect butternut trees to bear, on
an average, an enormous crop of nuts once in five years, a fairly large
crop once in three years, with little or no crop the remaining years.
As a seedling tree of two or three years, the butternut is
indistinguishable from the black walnut except to a very discerning and
practiced eye, especially in the autumn after its leaves have fallen. As
the trees grow older, the difference in their bark becomes more
apparent, that of the butternut remaining smooth for many years, as
contrasted to the bark on black walnut trees which begins to roughen on
the main trunk early in its life. Bark on a butternut may still be
smooth when the tree is ten years old. Forest seedlings of butternut,
when one or two years old, are easily transplanted if the soil is
congenial to their growth. Although the tree will do well on many types
of soil, it prefers one having a limestone base, just as the English
walnut does.
A butternut seedling usually requires several more years of growth than
a black walnut does before it comes into bearing, although this varies
with climate and soil. It is impossible to be exact, but I think I may
safely say that it requires at least ten years of growing before a
seedling butternut tree will bear any nuts. Of course, exceptions will
occasionally occur.
As a butternut tree matures, it spreads out much like an apple or
chestnut tree. Of course, it must have enough room to do so, an
important factor in raising any nut tree. Enough room and sunlight
hasten bearing-age and insure larger crops of finer nuts. Grafting
valuable varieties of butternut on black walnut stock will also hasten
bearing. I have had such grafts produce nuts the same year the grafting
was done and these trees continued to grow rapidly and produce annually.
However, they were not easy to graft, the stubborn reluctance of the
butternut top to accept transplantation to a foreign stock being well
known. This factor will probably always cause grafted butternut trees to
be higher in price than black walnut or hickory. The reverse graft,
i.e., black walnut on butternut should never be practiced for although
successful, the black walnut overgrows the stock and results in an
unproductive tree. Specimens 25 or more years old prove this to be a
fact.
Butternut trees are good feeders. They respond well to cultivation and
lend themselves to being grafted upon, although, from my own experience,
I question their usefulness as a root stock. I have found that when I
grafted black walnuts, English walnuts or heartnuts on butternut stock,
the top or grafted part of the tree became barren except for an
occasional handful of nuts, even on very large trees. Since this has
occurred throughout the many years of my nut culture work, I think it
should be given serious consideration before butternut is used as a root
stock for other species of nut trees.
[Illustration: _Weschcke Butternut. Smooth shallow convolutions of shell
allow kernels to drop out freely. Drawing by Wm. Kuehn._]
I had the good luck to discover an easy-cracking variety of butternut in
River Falls, Wisconsin, in 1934, which I have propagated commercially
and which carries my name. A medium-sized nut, it has the requisite
properties for giving it a varietal name, for it cracks mostly along the
sutural lines and its internal structure is so shallow that the kernel
will fall out if a half-shell is turned upside down. I received one of
those surprises which sometimes occur when a tree is asexually
propagated when I grafted scions from this butternut on black walnut
stock. The resulting nuts were larger than those on the parent tree and
their hulls peeled off with almost no effort. Whether these features
continue after the trees become older is something I shall observe with
interest.
[Illustration: _Self hulling Butternut. Weschcke variety. Drawing by Wm.
Kuehn._]
The nearly self-hulling quality of these nuts makes them very clean to
handle. The absence of hulls in cracking butternuts not only does away
with the messiness usually involved, but also it allows more accurate
cracking and more sanitary handling of the kernels. In 1949 I noticed a
new type of butternut growing near the farm residence. This butternut
was fully twice as large as the Weschcke and had eight prominent ridges.
The nut proved to be even better than the older variety and we intend to
test it further by grafting it on butternuts and black walnut stocks.
Although hand-operated nutcrackers have been devised to crack these and
other wild nuts, they are not as fast as a hammer. If one protects the
hand by wearing a glove and stands the butternut on a solid iron base,
hitting the pointed end with a hammer, it is quite possible to
accumulate a pint of clean nut meats in half an hour.
The butternut tree is one whose lumber may be put to many uses. It is
light but very tough and stringy and when planed and sanded, it absorbs
varnish and finishes very well. Although not as dark in natural color as
black walnut, butternut resembles it in grain. When butternut has been
stained to represent black walnut, it is only by their weight that they
can be distinguished. In late years, natural butternut has become
popular as an interior finish and for furniture, being sold as "blonde
walnut," "French walnut," or "white walnut," in my opinion very improper
names. I see no reason for calling it by other than its own. Depletion
of forests of butternut trees brings its lumber value up in price nearly
to that of fine maple or birch, approaching that of black walnut in some
places.
I have run several thousand feet of butternut lumber from my farmland
through my own sawmill and used it for a variety of purposes. It is
probably the strongest wood for its weight except spruce. I have used it
successfully to make propellers which operate electric generators for
deriving power from the wind. Because butternut is so light and,
properly varnished, resists weathering and decay to so great an extent,
I have found it the best material I have ever tried for such
construction. In building a small electric car for traveling around the
orchards, I used butternut rather than oak or metal, which saved at
least 100 pounds of weight, an important matter since the source of the
car's power is automobile storage batteries.
Butternut is very durable in contact with the ground and is used for
fence posts on farms where it is plentiful. Bird houses built of this
wood will last indefinitely, even a lifetime if they are protected with
paint or varnish. Butternut is like red cedar in this respect, although
much stronger. Stories have been told of black walnut logs which, after
lying unused for fifty years, have been sawed into lumber and found to
be still in excellent condition. It is quite likely that the same could
be said of butternut for these woods are very much alike in the degree
of their durability and resistance to weather.
An incidental value butternut trees have is their ability to bleed
freely in the spring if the outer bark is cut. Therefore, they can be
tapped like maple trees and their sap boiled down to make a sweet syrup.
It does not have the sugar content that the Stabler black walnut has,
however. Another possible use is suggested by the shells of butternuts
which, even when buried in the ground, show great resistance to decay. I
have found them to be still intact and possessing some strength after
being covered by earth for fifteen years. This indicates that they might
be used with a binder in a composition material. Their extreme hardness
also offers a good wearing surface.
[Illustration: _Electrically operated wagon constructed of native
butternut wood known for strength and light weight as well as
durability. Author's sons aboard. Photo by C. Weschcke 1941._]
Not only good things can be said of the butternut tree and it would be
wrong to avoid mentioning the deleterious effect that a butternut tree
may have on other trees planted within the radius of its root system. I
have had several experiences of this kind. One butternut tree on my
farm, having a trunk six inches in diameter, killed every Mugho pine
within the radius of its root system. This amounted to between 50 and
100 pines. Their death could not be attributed to the shade cast by the
butternut as Mugho pines are very tolerant of shade. As the first
branches of the butternut were more than three feet off the ground, the
pines could not have been influenced by the top system of the tree nor
do I believe that it was due to fallen leaves, but rather directly to
the greatly ramified roots. Large evergreens, such as Colorado blue
spruce, native white pine, limber pine and Jeffrey pine are known to
have been similarly influenced. While small butternut trees do not, in
my experience, have this effect, this may be explained by the fact that
the radius of their root systems is much more limited. Most plants,
other than pines, thrive within the influence of butternut roots,
however, and it certainly does not damage pasture grass as some of the
country's best grazing land is among such trees. The damage results from
a chemical known as Juglone which is elaborated by the root system and
when the roots of the butternut cross those of its evergreen neighbor,
this acts as a poison to the evergreen and may kill it.
[Illustration: _An 8-foot propeller of butternut wood is the prime mover
for wind power generator which in a brisk wind generated 110 volts and
10 amperes at 300 RPM._]
The butternut is attacked by one serious disease which is in the nature
of a blight (melanconium oblongum), since it is transmitted through
spores. It usually attacks old trees, the branches of the top part
dying, and the bark on the main trunk becoming loose. The disease
progresses slowly and I have seen large trees infected for twelve or
fifteen years, continuing to bear fine crops. It does have a very
weakening effect, though, and eventually saps the life from the tree
long before its natural span of life of about fifty years is over.